Plain Reckoner

LLM API Cost Calculator

Estimate real monthly LLM API spend including the Batch API discount and prompt caching — and see what the cache minimum-prefix rule silently costs you.

Measured by us — our own data, as of 2026-08-26 · source

Get the data behind this

We publish what we measure — refreshed numbers, what changed, and what it means. No more than weekly.